Thanks for all the votes guys, I'm really surprised for it to be doing so well with how clean and awesome this weeks entries are!
440, you went over by more than 25px, you've got an extra chunk of 70 x 25 pixels when you look at the dimensions. The way I see it, yeah, it's not a big deal... so what's so hard about making an image just that much smaller to have your drop shadow? I look at the preview size limit as a way of making sure we all have roughly the same canvas to work with to "advertise" our entry. If it's over the size limit, it is stretching the rules, no argument about it.
There's one thing I don't mind though, which was also offering it as a wallpaper 👍